Troi loses her empathic abilities while the Enterprise is trapped in a two-dimensional field and being drawn with it toward a cosmic string that will destroy the Enterprise.

Whoopi Goldberg (Guinan)
Kim Braden (Ensign Janet Brooks)
Mary Kohnert (Ensign Tess Allenby)

• Riker refers to Deanna as "imzadi" (Betazoid for "beloved"), which is the first time the word has been heard since Season 2 ("Shades of Gray"). We won't hear it again until the 5th season (a "flashback" in "Violations") and then the 7th season ("Thine Own Self").